Tetrahymena: an easy alternative for Paramecium
By Johanna E. Speksnijder and Elle Bijmolt, Deaprtment of Genetics,
Center for Biological Sciences, University of Groningen, PO Box
14, 9750 AA Haren, The Netherlands
We now routinely use Tetrahymena cultures as an alternative for
Paramecium to feed the smallest baby fish. Tetrahymena has two
advantages, namely that the culture medium contains only few
components and is easy to prepare, and that sterile cultures are
commercially available from the Culture Collection of Algae and
Protozoa, Freshwater Biological Association, The Ferry House,
Ambleside, Cumbria LA22 0LP, UK; phone 44-5394-42468.
The strain we use is Tetrahymena pyriformis (catalogue no. CCAP
1630/1W), and the PPY culture medium is prepared as follows:
Dissolve 20 g proteose peptone and 2.5 g yeast extract in 1000 ml of
distilled water, and sterilize in batches of 200 ml in 500 ml
bottles. To start the culture, inocculate about 6 ml of dense culture
in 200 ml fresh PPY medium, and grow for 3-4 days at room
temperature with bottle caps opened one turn. These cultures can then
be harvested, or kept for up to several weeks at 15 degrees
centigrade to start new cultures. To harvest, centrifuge the cultures
for about 3 min at 500g, and rinse with PJ salt solution (see below).
Repeat twice to remove all PPY medium. Add a small volume of PPY
after the last step; the culture can now be used to feed the baby
fish. Using Tetrahymena, we have been able to grow babyfish with
survival rates comparable to those obtained with Paramecium.
PJ (Prescotts & James's) solution:
Make up the following three stock solutions, each in 100 ml distilled
water: 1) 0.433 g CaCl2.2H2O and 0.162 g KCl; 2) 0.512 g K2HPO4; 3)
0.280 g MgSO4.7H2O. Add 1 ml of each stock solution to 1 liter
distilled water.